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Howard Leadmon

2015-Dec-09 09:58 UTC

[CentOS-virt] How to manually add a new interface to a bridge device?

How do you decide what MAC address to use for that VM interface?   As I just
tried to change the MAC to some other value close, like I made
'52:54:00:34:e1:21' into say '52:54:00:34:e1:32', and when I try
and load it
in, I get the following:

 

error: XML error: Attempted double use of PCI Address '0:0:4.0'

 

 

Here is one of my network entries:

 

    <interface type='bridge'>

      <mac address='52:54:00:34:e1:21'/>

      <source bridge='br1'/>

      <model type='virtio'/>

      <address type='pci' domain='0x0000' bus='0x00'
slot='0x04'
function='0x0'/>

    </interface>

 

 

---

Howard 

 

From: centos-virt-bounces at centos.org [mailto:centos-virt-bounces at
centos.org]
On Behalf Of Zoltan Frombach
Sent: Wednesday, December 9, 2015 4:24 AM
To: Discussion about the virtualization on CentOS <centos-virt at
centos.org>
Subject: Re: [CentOS-virt] How to manually add a new interface to a bridge
device?

 


You most definitely do not need to destroy and re-create a VM just to add a
2nd network interface.

I don't think those vnet interfaces got created by the host OS. I believe
those are created by KVM (or libvirt) when you start a VM. I could be wrong
though. But I just checked on my CentOS 6 KVM host machine and I see as many
vnet interfaces as many VMs are currently running (or if one VM has two
virtual network cards then of course that VM results two vnet interfaces
shown on the host). Here the relevant part from one such VM's XML file
(those XML files are under the /etc/libvirt/qemu directory on my CentOS host
) :

    <interface type='bridge'>
      <mac address='00:16:36:e2:20:ea'/>
      <source bridge='br0'/>
      <model type='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00'
slot='0x03'
function='0x0'/>
    </interface>
    <interface type='bridge'>
      <mac address='00:16:36:e2:20:eb'/>
      <source bridge='br600'/>
      <model type='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00'
slot='0x06'
function='0x0'/>
    </interface>

As you can see, there are two interfaces defined in this VM's XML file. One
is connected to the host's br0 interface and the 2nd is connected to the
host's br600 interface. You must make sure that all your mac addesses are
unique on your network though!!

After editing a VM's XML file with your favorite editor, you need to execute
this command:
virsh define /etc/libvirt/qemu/your-vm-name.xml
or just simply use this editor:
virsh edit your-vm-name
(but I hate vi, so I use my favorite editor and when I finished editing I
just run virsh define.)

I edited VM's XML files many times and I can add/remove virtual network
cards without problems.

Zoltan

On 12/9/2015 9:55 AM, Howard Leadmon wrote:

Tried that as well, but this has to be something that gets set at the OS
level and loaded, as if you look at dmesg output, you can see all the vnet??
nodes as the OS comes online.    So the question is, what is virt-install
doing that creates the needed vnet interface that is part of the bridge.   I
really had to kill and reload the VM just to load a second interface..

 

 

---

Howard Leadmon 

 

From: centos-virt-bounces at centos.org <mailto:centos-virt-bounces at
centos.org>
[mailto:centos-virt-bounces at centos.org] On Behalf Of Zoltan Frombach
Sent: Wednesday, December 9, 2015 2:42 AM
To: Discussion about the virtualization on CentOS
<mailto:centos-virt at centos.org> <centos-virt at centos.org>
Subject: Re: [CentOS-virt] How to manually add a new interface to a bridge
device?

 

I would stop the VM, edit its definition file (that's an XML file) and then
start it up. But be careful: After you edit the XML file, you need to
execute a command so KVM re-reads that file. I forgot that command, but you
can look it up on Google.

On Dec 9, 2015 7:52 AM, "Howard Leadmon" <howard at leadmon.net
<mailto:howard at leadmon.net> > wrote:

 

Maybe my google-fu is failing me, but I have spent the past couple hours
looking at how to add a vnet? Device to my KVM host running CentOS 6, and
for the life of me I can't get this going.    

 
>From all my research if I want to add a device I should just do 'brctl
addifbr1 vnet14' if I want to add a vnet14 to bridge br1.   When I do this, I
get:

 

# brctl addif br0 vnet14

interface vnet14 does not exist!

 

 

If I run a 'brctl show' I get the following:

 

# brctl show

bridge name     bridge id               STP enabled     interfaces

br0             8000.00237dd22a4c       no              eth0

                                                        vnet0

                                                        vnet10

                                                        vnet11

                                                        vnet13

                                                        vnet2

                                                       vnet3

                                                        vnet4

                                                        vnet6

                                                        vnet8

br1             8000.00237dd22a50       no              eth1

                                                        vnet1

                                                        vnet12

                                                        vnet5

                                                        vnet7

                                                        vnet9

 

 

Needless to say the existing vnet?? Devices are in use on guest VM's
currently.

 

When I create a new VM using virt-install, I usually add the following to my
command line:

 

--network=bridge:br0 --network=bridge:br1

 

I messed up building a new VM, and only added the br0 interface to the VM,
but need the br1 interface as well.  So my question is, or a pointer to how
I can add that br1 interface to my existing VM, and create the needed vnet14
interface for it to attach to?

 

If anyone can explain how to do this, or give me a good pointer on where the
info is on how to do this, it would sure be a huge help..

 

Thanks.

 

 

---

Howard Leadmon 

 


_______________________________________________
CentOS-virt mailing list
CentOS-virt at centos.org <mailto:CentOS-virt at centos.org> 
https://lists.centos.org/mailman/listinfo/centos-virt






_______________________________________________
CentOS-virt mailing list
CentOS-virt at centos.org <mailto:CentOS-virt at centos.org> 
https://lists.centos.org/mailman/listinfo/centos-virt

 

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Zoltan Frombach

2015-Dec-09 10:05 UTC

head link

[CentOS-virt] How to manually add a new interface to a bridge device?

The MAC address you gave is fine. I use random MAC addresses just like 
you did.

Your PCI bus address also has to be unique within a given VM. I'm sorry, 
I forgot to mention that. Look at my configuration example I sent. These 
are emulated (virtual) network cards attached to the emulated (virtual) 
PCI bus of the virtual machine. Two network cards cannot have the same 
MAC address and they cannot be on the same PCI bus address either. Your 
VM's are emulated physical machines with their own BIOS, etc.

Zoltan

On 12/9/2015 10:58 AM, Howard Leadmon wrote:>
> How do you decide what MAC address to use for that VM interface?   As 
> I just tried to change the MAC to some other value close, like I made 
> '52:54:00:34:e1:21' into say '52:54:00:34:e1:32', and when
I try and
> load it in, I get the following:
>
> error: XML error: Attempted double use of PCI Address '0:0:4.0'
>
> Here is one of my network entries:
>
> <interface type='bridge'>
>
> <mac address='52:54:00:34:e1:21'/>
>
> <source bridge='br1'/>
>
> <model type='virtio'/>
>
> <address type='pci' domain='0x0000' bus='0x00'
slot='0x04'
> function='0x0'/>
>
> </interface>
>
> ---
>
> Howard
>
> *From:*centos-virt-bounces at centos.org 
> [mailto:centos-virt-bounces at centos.org] *On Behalf Of *Zoltan Frombach
> *Sent:* Wednesday, December 9, 2015 4:24 AM
> *To:* Discussion about the virtualization on CentOS 
> <centos-virt at centos.org>
> *Subject:* Re: [CentOS-virt] How to manually add a new interface to a 
> bridge device?
>
>
> You most definitely do not need to destroy and re-create a VM just to 
> add a 2nd network interface.
>
> I don't think those vnet interfaces got created by the host OS. I 
> believe those are created by KVM (or libvirt) when you start a VM. I 
> could be wrong though. But I just checked on my CentOS 6 KVM host 
> machine and I see as many vnet interfaces as many VMs are currently 
> running (or if one VM has two virtual network cards then of course 
> that VM results two vnet interfaces shown on the host). Here the 
> relevant part from one such VM's XML file (those XML files are under 
> the /etc/libvirt/qemu directory on my CentOS host ) :
>
>     <interface type='bridge'>
>       <mac address='00:16:36:e2:20:ea'/>
>       <source bridge='br0'/>
>       <model type='virtio'/>
>       <address type='pci' domain='0x0000'
bus='0x00' slot='0x03'
> function='0x0'/>
>     </interface>
>     <interface type='bridge'>
>       <mac address='00:16:36:e2:20:eb'/>
>       <source bridge='br600'/>
>       <model type='virtio'/>
>       <address type='pci' domain='0x0000'
bus='0x00' slot='0x06'
> function='0x0'/>
>     </interface>
>
> As you can see, there are two interfaces defined in this VM's XML 
> file. One is connected to the host's br0 interface and the 2nd is 
> connected to the host's br600 interface. You must make sure that all 
> your mac addesses are unique on your network though!!
>
> After editing a VM's XML file with your favorite editor, you need to 
> execute this command:
> virsh define /etc/libvirt/qemu//your-vm-name/.xml
> or just simply use this editor:
> virsh edit /your-vm-name/
> (but I hate vi, so I use my favorite editor and when I finished 
> editing I just run virsh define.)
>
> I edited VM's XML files many times and I can add/remove virtual 
> network cards without problems.
>
> Zoltan
>
> On 12/9/2015 9:55 AM, Howard Leadmon wrote:
>
>     Tried that as well, but this has to be something that gets set at
>     the OS level and loaded, as if you look at dmesg output, you can
>     see all the vnet?? nodes as the OS comes online.    So the
>     question is, what is virt-install doing that creates the needed
>     vnet interface that is part of the bridge.   I really had to kill
>     and reload the VM just to load a second interface..
>
>     ---
>
>     Howard Leadmon
>
>     *From:*centos-virt-bounces at centos.org
>     <mailto:centos-virt-bounces at centos.org>
>     [mailto:centos-virt-bounces at centos.org] *On Behalf Of *Zoltan
Frombach
>     *Sent:* Wednesday, December 9, 2015 2:42 AM
>     *To:* Discussion about the virtualization on CentOS
>     <centos-virt at centos.org> <mailto:centos-virt at
centos.org>
>     *Subject:* Re: [CentOS-virt] How to manually add a new interface
>     to a bridge device?
>
>     I would stop the VM, edit its definition file (that's an XML file)
>     and then start it up. But be careful: After you edit the XML file,
>     you need to execute a command so KVM re-reads that file. I forgot
>     that command, but you can look it up on Google.
>
>     On Dec 9, 2015 7:52 AM, "Howard Leadmon" <howard at
leadmon.net
>     <mailto:howard at leadmon.net>> wrote:
>
>         Maybe my google-fu is failing me, but I have spent the past
>         couple hours looking at how to add a vnet? Device to my KVM
>         host running CentOS 6, and for the life of me I can?t get this
>         going.
>
>         From all my research if I want to add a device I should just
>         do ?brctl addif br1 vnet14? if I want to add a vnet14 to
>         bridge br1.   When I do this, I get:
>
>         # brctl addif br0 vnet14
>
>         interface vnet14 does not exist!
>
>         If I run a ?brctl show? I get the following:
>
>         # brctl show
>
>         bridge name     bridge id               STP enabled interfaces
>
>         br0 8000.00237dd22a4c       no              eth0
>
>         vnet0
>
>         vnet10
>
>         vnet11
>
>         vnet13
>
>         vnet2
>
>                                                                vnet3
>
>         vnet4
>
>         vnet6
>
>         vnet8
>
>         br1        8000.00237dd22a50       no eth1
>
>         vnet1
>
>         vnet12
>
>         vnet5
>
>                                                vnet7
>
>         vnet9
>
>         Needless to say the existing vnet?? Devices are in use on
>         guest VM?s currently.
>
>         When I create a new VM using virt-install, I usually add the
>         following to my command line:
>
>         --network=bridge:br0 --network=bridge:br1
>
>         I messed up building a new VM, and only added the br0
>         interface to the VM, but need the br1 interface as well.  So
>         my question is, or a pointer to how I can add that br1
>         interface to my existing VM, and create the needed vnet14
>         interface for it to attach to?
>
>         If anyone can explain how to do this, or give me a good
>         pointer on where the info is on how to do this, it would sure
>         be a huge help..
>
>         Thanks?
>
>         ---
>
>         Howard Leadmon
>
>
>         _______________________________________________
>         CentOS-virt mailing list
>         CentOS-virt at centos.org <mailto:CentOS-virt at centos.org>
>         https://lists.centos.org/mailman/listinfo/centos-virt
>
>
>
>
>     _______________________________________________
>
>     CentOS-virt mailing list
>
>     CentOS-virt at centos.org <mailto:CentOS-virt at centos.org>
>
>     https://lists.centos.org/mailman/listinfo/centos-virt
>
>
>
> _______________________________________________
> CentOS-virt mailing list
> CentOS-virt at centos.org
> https://lists.centos.org/mailman/listinfo/centos-virt
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Zoltan Frombach

2015-Dec-09 10:38 UTC

head link

[CentOS-virt] How to manually add a new interface to a bridge device?

BTW, adding a 2nd virtual nic to a guest can also be done with command 
line tools (I just googled this for you) :
https://kashyapc.fedorapeople.org/virt/add-network-card-in-guest.txt
( It came up as 1st result when I searched for: virsh add network 
interface to existing guest )

But if you look at the bottom of this guide, they also mention that if 
something goes wrong, they resort to using virsh edit just like I 
suggested to you. See, I prefer to edit a configuration file rather then 
issuing long and complicated commands on the CLI. However, being able to 
add a 2nd nic to a live guest is nice though and that could only be 
achieved with the CLI command. As you can see, you can even add nic's to 
a VM without having to reboot it.

Zoltan

On 12/9/2015 10:58 AM, Howard Leadmon wrote:>
> How do you decide what MAC address to use for that VM interface?   As 
> I just tried to change the MAC to some other value close, like I made 
> '52:54:00:34:e1:21' into say '52:54:00:34:e1:32', and when
I try and
> load it in, I get the following:
>
> error: XML error: Attempted double use of PCI Address '0:0:4.0'
>
> Here is one of my network entries:
>
> <interface type='bridge'>
>
> <mac address='52:54:00:34:e1:21'/>
>
> <source bridge='br1'/>
>
> <model type='virtio'/>
>
> <address type='pci' domain='0x0000' bus='0x00'
slot='0x04'
> function='0x0'/>
>
> </interface>
>
> ---
>
> Howard
>
> *From:*centos-virt-bounces at centos.org 
> [mailto:centos-virt-bounces at centos.org] *On Behalf Of *Zoltan Frombach
> *Sent:* Wednesday, December 9, 2015 4:24 AM
> *To:* Discussion about the virtualization on CentOS 
> <centos-virt at centos.org>
> *Subject:* Re: [CentOS-virt] How to manually add a new interface to a 
> bridge device?
>
>
> You most definitely do not need to destroy and re-create a VM just to 
> add a 2nd network interface.
>
> I don't think those vnet interfaces got created by the host OS. I 
> believe those are created by KVM (or libvirt) when you start a VM. I 
> could be wrong though. But I just checked on my CentOS 6 KVM host 
> machine and I see as many vnet interfaces as many VMs are currently 
> running (or if one VM has two virtual network cards then of course 
> that VM results two vnet interfaces shown on the host). Here the 
> relevant part from one such VM's XML file (those XML files are under 
> the /etc/libvirt/qemu directory on my CentOS host ) :
>
>     <interface type='bridge'>
>       <mac address='00:16:36:e2:20:ea'/>
>       <source bridge='br0'/>
>       <model type='virtio'/>
>       <address type='pci' domain='0x0000'
bus='0x00' slot='0x03'
> function='0x0'/>
>     </interface>
>     <interface type='bridge'>
>       <mac address='00:16:36:e2:20:eb'/>
>       <source bridge='br600'/>
>       <model type='virtio'/>
>       <address type='pci' domain='0x0000'
bus='0x00' slot='0x06'
> function='0x0'/>
>     </interface>
>
> As you can see, there are two interfaces defined in this VM's XML 
> file. One is connected to the host's br0 interface and the 2nd is 
> connected to the host's br600 interface. You must make sure that all 
> your mac addesses are unique on your network though!!
>
> After editing a VM's XML file with your favorite editor, you need to 
> execute this command:
> virsh define /etc/libvirt/qemu//your-vm-name/.xml
> or just simply use this editor:
> virsh edit /your-vm-name/
> (but I hate vi, so I use my favorite editor and when I finished 
> editing I just run virsh define.)
>
> I edited VM's XML files many times and I can add/remove virtual 
> network cards without problems.
>
> Zoltan
>
> On 12/9/2015 9:55 AM, Howard Leadmon wrote:
>
>     Tried that as well, but this has to be something that gets set at
>     the OS level and loaded, as if you look at dmesg output, you can
>     see all the vnet?? nodes as the OS comes online.    So the
>     question is, what is virt-install doing that creates the needed
>     vnet interface that is part of the bridge.   I really had to kill
>     and reload the VM just to load a second interface..
>
>     ---
>
>     Howard Leadmon
>
>     *From:*centos-virt-bounces at centos.org
>     <mailto:centos-virt-bounces at centos.org>
>     [mailto:centos-virt-bounces at centos.org] *On Behalf Of *Zoltan
Frombach
>     *Sent:* Wednesday, December 9, 2015 2:42 AM
>     *To:* Discussion about the virtualization on CentOS
>     <centos-virt at centos.org> <mailto:centos-virt at
centos.org>
>     *Subject:* Re: [CentOS-virt] How to manually add a new interface
>     to a bridge device?
>
>     I would stop the VM, edit its definition file (that's an XML file)
>     and then start it up. But be careful: After you edit the XML file,
>     you need to execute a command so KVM re-reads that file. I forgot
>     that command, but you can look it up on Google.
>
>     On Dec 9, 2015 7:52 AM, "Howard Leadmon" <howard at
leadmon.net
>     <mailto:howard at leadmon.net>> wrote:
>
>         Maybe my google-fu is failing me, but I have spent the past
>         couple hours looking at how to add a vnet? Device to my KVM
>         host running CentOS 6, and for the life of me I can?t get this
>         going.
>
>         From all my research if I want to add a device I should just
>         do ?brctl addif br1 vnet14? if I want to add a vnet14 to
>         bridge br1.   When I do this, I get:
>
>         # brctl addif br0 vnet14
>
>         interface vnet14 does not exist!
>
>         If I run a ?brctl show? I get the following:
>
>         # brctl show
>
>         bridge name     bridge id               STP enabled interfaces
>
>         br0 8000.00237dd22a4c       no              eth0
>
>         vnet0
>
>         vnet10
>
>         vnet11
>
>         vnet13
>
>         vnet2
>
>                                                                vnet3
>
>         vnet4
>
>         vnet6
>
>         vnet8
>
>         br1        8000.00237dd22a50       no eth1
>
>         vnet1
>
>         vnet12
>
>         vnet5
>
>                                                vnet7
>
>         vnet9
>
>         Needless to say the existing vnet?? Devices are in use on
>         guest VM?s currently.
>
>         When I create a new VM using virt-install, I usually add the
>         following to my command line:
>
>         --network=bridge:br0 --network=bridge:br1
>
>         I messed up building a new VM, and only added the br0
>         interface to the VM, but need the br1 interface as well.  So
>         my question is, or a pointer to how I can add that br1
>         interface to my existing VM, and create the needed vnet14
>         interface for it to attach to?
>
>         If anyone can explain how to do this, or give me a good
>         pointer on where the info is on how to do this, it would sure
>         be a huge help..
>
>         Thanks?
>
>         ---
>
>         Howard Leadmon
>
>
>         _______________________________________________
>         CentOS-virt mailing list
>         CentOS-virt at centos.org <mailto:CentOS-virt at centos.org>
>         https://lists.centos.org/mailman/listinfo/centos-virt
>
>
>
>
>     _______________________________________________
>
>     CentOS-virt mailing list
>
>     CentOS-virt at centos.org <mailto:CentOS-virt at centos.org>
>
>     https://lists.centos.org/mailman/listinfo/centos-virt
>
>
>
> _______________________________________________
> CentOS-virt mailing list
> CentOS-virt at centos.org
> https://lists.centos.org/mailman/listinfo/centos-virt
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Howard Leadmon

2015-Dec-09 17:47 UTC

head link

[CentOS-virt] How to manually add a new interface to a bridge device?

That is exactly what I was looking for, and worked perfectly, and will now
be added to my notes on working with VM's.   I figured it was a matter of me
just not using the right search words in google, but damn if I could find
that page, and I tried.  

 

Using the info on that page, I added an interface, and it's live and
running..

 

 

---

Howard Leadmon 

 

From: centos-virt-bounces at centos.org [mailto:centos-virt-bounces at
centos.org]
On Behalf Of Zoltan Frombach
Sent: Wednesday, December 9, 2015 5:38 AM
To: Discussion about the virtualization on CentOS <centos-virt at
centos.org>
Subject: Re: [CentOS-virt] How to manually add a new interface to a bridge
device?

 

BTW, adding a 2nd virtual nic to a guest can also be done with command line
tools (I just googled this for you) :
https://kashyapc.fedorapeople.org/virt/add-network-card-in-guest.txt
( It came up as 1st result when I searched for: virsh add network interface
to existing guest )

But if you look at the bottom of this guide, they also mention that if
something goes wrong, they resort to using virsh edit just like I suggested
to you. See, I prefer to edit a configuration file rather then issuing long
and complicated commands on the CLI. However, being able to add a 2nd nic to
a live guest is nice though and that could only be achieved with the CLI
command. As you can see, you can even add nic's to a VM without having to
reboot it.

Zoltan

On 12/9/2015 10:58 AM, Howard Leadmon wrote:

How do you decide what MAC address to use for that VM interface?   As I just
tried to change the MAC to some other value close, like I made
'52:54:00:34:e1:21' into say '52:54:00:34:e1:32', and when I try
and load it
in, I get the following:

 

error: XML error: Attempted double use of PCI Address '0:0:4.0'

 

 

Here is one of my network entries:

 

    <interface type='bridge'>

      <mac address='52:54:00:34:e1:21'/>

      <source bridge='br1'/>

      <model type='virtio'/>

      <address type='pci' domain='0x0000' bus='0x00'
slot='0x04'
function='0x0'/>

    </interface>

 

 

---

Howard 

 

From: centos-virt-bounces at centos.org <mailto:centos-virt-bounces at
centos.org>
[mailto:centos-virt-bounces at centos.org] On Behalf Of Zoltan Frombach
Sent: Wednesday, December 9, 2015 4:24 AM
To: Discussion about the virtualization on CentOS
<mailto:centos-virt at centos.org> <centos-virt at centos.org>
Subject: Re: [CentOS-virt] How to manually add a new interface to a bridge
device?

 


You most definitely do not need to destroy and re-create a VM just to add a
2nd network interface.

I don't think those vnet interfaces got created by the host OS. I believe
those are created by KVM (or libvirt) when you start a VM. I could be wrong
though. But I just checked on my CentOS 6 KVM host machine and I see as many
vnet interfaces as many VMs are currently running (or if one VM has two
virtual network cards then of course that VM results two vnet interfaces
shown on the host). Here the relevant part from one such VM's XML file
(those XML files are under the /etc/libvirt/qemu directory on my CentOS host
) :

    <interface type='bridge'>
      <mac address='00:16:36:e2:20:ea'/>
      <source bridge='br0'/>
      <model type='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00'
slot='0x03'
function='0x0'/>
    </interface>
    <interface type='bridge'>
      <mac address='00:16:36:e2:20:eb'/>
      <source bridge='br600'/>
      <model type='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00'
slot='0x06'
function='0x0'/>
    </interface>

As you can see, there are two interfaces defined in this VM's XML file. One
is connected to the host's br0 interface and the 2nd is connected to the
host's br600 interface. You must make sure that all your mac addesses are
unique on your network though!!

After editing a VM's XML file with your favorite editor, you need to execute
this command:
virsh define /etc/libvirt/qemu/your-vm-name.xml
or just simply use this editor:
virsh edit your-vm-name
(but I hate vi, so I use my favorite editor and when I finished editing I
just run virsh define.)

I edited VM's XML files many times and I can add/remove virtual network
cards without problems.

Zoltan

On 12/9/2015 9:55 AM, Howard Leadmon wrote:

Tried that as well, but this has to be something that gets set at the OS
level and loaded, as if you look at dmesg output, you can see all the vnet??
nodes as the OS comes online.    So the question is, what is virt-install
doing that creates the needed vnet interface that is part of the bridge.   I
really had to kill and reload the VM just to load a second interface..

 

 

---

Howard Leadmon 

 

From: centos-virt-bounces at centos.org <mailto:centos-virt-bounces at
centos.org>
[mailto:centos-virt-bounces at centos.org] On Behalf Of Zoltan Frombach
Sent: Wednesday, December 9, 2015 2:42 AM
To: Discussion about the virtualization on CentOS
<mailto:centos-virt at centos.org> <centos-virt at centos.org>
Subject: Re: [CentOS-virt] How to manually add a new interface to a bridge
device?

 

I would stop the VM, edit its definition file (that's an XML file) and then
start it up. But be careful: After you edit the XML file, you need to
execute a command so KVM re-reads that file. I forgot that command, but you
can look it up on Google.

On Dec 9, 2015 7:52 AM, "Howard Leadmon" <howard at leadmon.net
<mailto:howard at leadmon.net> > wrote:

 

Maybe my google-fu is failing me, but I have spent the past couple hours
looking at how to add a vnet? Device to my KVM host running CentOS 6, and
for the life of me I can't get this going.    

 
>From all my research if I want to add a device I should just do 'brctl
addifbr1 vnet14' if I want to add a vnet14 to bridge br1.   When I do this, I
get:

 

# brctl addif br0 vnet14

interface vnet14 does not exist!

 

 

If I run a 'brctl show' I get the following:

 

# brctl show

bridge name     bridge id               STP enabled     interfaces

br0             8000.00237dd22a4c       no              eth0

                                                        vnet0

                                                        vnet10

                                                        vnet11

                                                        vnet13

                                                        vnet2

                                                       vnet3

                                                        vnet4

                                                        vnet6

                                                        vnet8

br1             8000.00237dd22a50       no              eth1

                                                        vnet1

                                                        vnet12

                                                        vnet5

                                                        vnet7

                                                        vnet9

 

 

Needless to say the existing vnet?? Devices are in use on guest VM's
currently.

 

When I create a new VM using virt-install, I usually add the following to my
command line:

 

--network=bridge:br0 --network=bridge:br1

 

I messed up building a new VM, and only added the br0 interface to the VM,
but need the br1 interface as well.  So my question is, or a pointer to how
I can add that br1 interface to my existing VM, and create the needed vnet14
interface for it to attach to?

 

If anyone can explain how to do this, or give me a good pointer on where the
info is on how to do this, it would sure be a huge help..

 

Thanks.

 

 

---

Howard Leadmon 

 


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